In-vivo condition monitoring of metallic implants by electrochemical techniques

Abstract

The invention relates to a replacement metallic prosthesis to be implanted which contains means monitor its condition during use in order to allow an early detection of failure or insufficient functionality, wherein said means comprise implanted sensors and electronics ( 3 ) and a remote device ( 9 ), to measure the implant's function and degradation during its life span, wherein said sensors are electro chemical sensors with electrodes ( 1 ). The prosthesis according to the invention may also be used to promote bone growth. The invention also relates to a method using the device of the invention.

1 . A metallic prosthesis to be implanted in a body, for example a human or animal body, which contains means to monitor its condition during use in order to allow an early detection of failure or insufficient functionality, and/or to apply a stimulating condition, wherein said means comprise at least implanted sensors with electrodes and electronic device and a remote device, to measure the implant's function and degradation during its life span, wherein said sensors are electrochemical sensors. 
     
     
         2 . The prosthesis according to  claim 1 , wherein said electronic device comprises at least a signal processor, a communication subsystem. 
     
     
         3 . The prosthesis according to  claim 1 , wherein the communication subsystem comprises a Radio Frequency front-end and its antenna which allows the wireless external downloading of the measured data by the electrodes or the application of energy to apply the stimulating condition. 
     
     
         4 . The prosthesis as defined in  claim 3 , wherein the electronic device is passive and said remote device comprises an energy source. 
     
     
         5 . The prosthesis according to  claim 1 , wherein micro-electrodes are used. 
     
     
         6 . The prosthesis according to  claim 1 , wherein the electrodes are made of Ag or tungsten, or another equivalent material. 
     
     
         7 . The prosthesis according to  claim 1 , wherein said prosthesis is a hip prosthesis. 
     
     
         8 . The prosthesis according to  claim 1 , wherein said prosthesis is a knee prosthesis. 
     
     
         9 . A method of measuring the functionality of an implanted prosthesis using the prosthesis as defined in  claim 1 . 
     
     
         10 . The method according to  claim 9 , wherein measuring the functionality of an implanted prosthesis utilizes one or more of Open Circuit Potential (OCP), Electrochemical Impedance Spectroscopy (EIS), or Polarization Resistance (Rp) measurements. 
     
     
         11 . A method of using an implanted prosthesis with electrodes as defined in  claim 1 , wherein said prosthesis is used to promote bone growth by applying an electric current to the environment of the electrodes of said prosthesis.